A Russian worshipper lights a candle as she attends a special mass dedicated to the arrival of the Russian Orthodox Patriarch Kirill at the Dionisos Aeropagitos church in Athens on June 1, 2013. The Russian Orthodox Patriarch begun a week-long visit to Greece for talks with church and political leaders. AFP PHOTO / LOUISA GOULIAMAKI (Photo credit should read LOUISA GOULIAMAKI/AFP/Getty Images)

Americans are highly likely to inflate their amount of religious participation – if they even attend religious services at all. (LOUISA GOULIAMAKI/AFP/Getty Images)

WASHINGTON (CBS DC) — Americans from all subgroups are highly likely to significantly inflate their amount of religious participation – if they attend religious services at all.

A new Public Religion Research Institute (PRRI) survey finds that Catholics and white mainline Protestants still see the most “social desirability” of attending church, with fewer than 3-in-10 (29 percent) reporting that they seldom or never attend religious services – compared to 45 percent who said that in a self-administered online survey.

Catholics are less than half as likely to report seldom or never attending religious services when responding to the telephone versus online (15 percent vs. 33 percent).

Among white evangelical Protestants, the differences are less glaring: 9 percent report they seldom or never attend religious services when speaking with a live interviewer, compared to 17 percent who report the same in a self-administered survey.

Only 14 percent of black Protestants report seldom or never attending church through the telephone survey, compared to nearly one-quarter (24 percent) on the online survey.

And despite a growing number of Americans who label themselves as “unaffiliated” to any religious practice, many of these people in the U.S. still exaggerate how often they attend religious ceremonies.

“The existence of religious participation inflation demonstrates that church attendance remains a strong social norm in the U.S.,’” said Robert P. Jones, co-author of the study and CEO of PRRI. “The impact of these norms – what social scientists call ‘social desirability bias’ – is that respondents talking to live interviewers on the telephone are less willing to admit lower levels of participation in an activity deemed to be socially good. Respondents completing the survey privately online are less apt to feel this pressure.”

Nearly three-quarters (73 percent) of religiously unaffiliated respondents said they seldom or never attend religious services in the telephone survey, but that number increased almost 20 percentage points to 91 percent in the self-administered online survey.

“Even among Americans who claim no religious affiliation, the social pressure to report at least nominal religious engagement is still quite strong,” said Daniel Cox, co-author of the study and PRRI’s Director of Research. “Very few people are willing to admit that they never attend religious services, even though many of us don’t.”